THEY say every journey starts with one step. Sometimes it starts in farce, too. Knowing it is essential to set off early from Beijing to visit the Great Wall before the tourist masses arrived, I arrange with my Chinese friend Qian for an 8am start. She holds out for 10.30am. We haggle and eventually compromise on 9am. Qian turns up at my hotel at 9.30am and then drives to a Starbucks for breakfast.

Leaving me in her car, she rushes inside. Seconds later a traffic policeman bangs on my window and makes it very clear I need to move. Given Beijing’s insane traffic, that is not something I am very keen to do. However, sliding across into the driving seat, I drive around the block in rush hour traffic. I am soon a nervous wreck. Every time I try to stop, the same traffic cop waves me on. On my third circuit, I eventually see Qian, tottering on high heels, chasing my tail, coffees and cakes in hand.

So a 10.30am start it is. It seems that, even in China, women tend to get want they want. Sure enough we are soon stuck behind an endless row of coaches and minivans bearing visitors to the wall, a flow of humanity streaming toward this most famous of sights. The Great Wall is China’s most visited tourist attraction and the most popular stretch is this one at Badaling, as it is only a few hours from Beijing. Inching along in slow traffic on an expressway, surrounded by the dull concrete buildings that blight China’s urban landscape, it is always a shock to suddenly see the so-familiar lines of the Great Wall appear beside the road. Somehow it feels as if there should be a much grander unveiling, instead of this first glimpse through high rises and billboards, with the mind distracted by traffic chaos.

Unless you have been to China, it is impossible to convey the size of the crowds you will see everywhere. With a population of more than a billion, everything is on a grand scale, from the Great Wall itself, to the number of people climbing it. China’s internal tourism market is huge, with some 1.4 billion domestic visitors in the first half of 2011, a rise of 12 percent. That’s a number equivalent to the country’s entire population on the move and, although it is a vast country, they all want to visit the “Long Wall” (as it is known in Chinese) at least once. “Visiting Beijing is a must for any Chinese who can afford it,” lecturer Lin Xuĕ tells me, “and the cream of this ‘worshipping our capital’ trip is to visit important national landmarks such as the ‘Great’ Wall, Tiananmen Square and the Forbidden City (in that order).”

Near the entrance to Badaling Great Wall, a bronze plaque with words from a poem of Chairman Mao Zedong reinforces this message: “If we fail to reach the Great Wall we are not men.” It is a must-do photo opportunity for every Chinese visitor, who position themselves in front of it in ways that might give the old communist a heart attack were he still alive to see it. An endless stream of young people in brightly coloured clothes strike poses straight from capitalist films and magazines. Finding the right time for a shot of your own is hard: standing in line is not the Chinese way and they push on, take their photo, and go, with no patience for foreign fools who think there might be a quiet moment. They keep themselves to themselves and make no effort to speak to the foreigner.

You might think something the size of the Great Wall would absorb any number of people. In the remote countryside, yes, but this close to China’s capital city, only those portions that have been rebuilt are considered safe enough for visitors.

In China, safety can be a relative concept. Worn smooth by the shuffling of countless feet, and with holes everywhere, the stone paving is treacherous. Near-vertical steps with narrow treads are bad enough going up. Going down, with a crowd pressing behind, seems like an accident waiting to happen. And yet, despite all the hassle of getting here, the tacky souvenir shops and the press of people around me, as I raise my head to the horizon and see the battlements fading into the haze of far-distant mountains, I am always awed to stand on the Great Wall. This truly is one of the World’s Seven Wonders.

It is an amazing sight, worth any effort to see, and a form of horizontal vertigo always seizes me. Vertigo is not the fear of falling from a height, but the fear of throwing yourself off. I want to start walking these wide ramparts and never stop. Given the searing noontide heat and the way the wall quickly deteriorates away from this showcase spot, not to mention Qian’s rather impractical high heels, it is a desire to be indulged another day. For now, it is time for lunch which, like any meal, is a very serious affair in China. The crowds thin significantly as the local eateries start to heave with customers and I have a few moments of relative isolation.

One man who did give in to the compulsion to keep walking was American William Edgar Geil who, after exploring 3,000 km of it, in 1909 wrote the first book about the Great Wall. The Baptist missionary had a dry sense of humour, as shown by his opening paragraph: “There is a Great Wall of China. So much the geographies tell everybody; but they do not make it clear whether it is built of china, or why it is, or how long it is, or how long it has been.” His book, full of detailed photos and vague but similarly amusing text, fed the West’s fascination with this exotic structure but also launched misconceptions that persist to this day, among them the claim that the Great Wall is visible from the moon.

In 1987, Briton William Lindesay also completed a 2,470 km trek from Jiayuguan (see below) in the dusty west to where it touches the Yellow Sea at Shanhaiguan. Now based in Beijing, he concentrates on exploring what he calls the Wild Wall, the untouched parts well away from tourists. As tourism and industry encroach on the land next to the wall, it loses its setting and becomes merely a glorified Disneyland. “The wall is an amazing thing. It is not only a building, it is a landscape,” he says. “But it is a victim of its own greatness. It meets modern and expanding China head on, in thousands of locations. It is difficult to protect because there is so much of it.”

That battle for protection, if it was ever joined, seems lost at Badaling and also a few miles away at Mutianyu, where the whole village serves tourists who come to see a stretch of wall made even more impressive by its mountain setting. First built in the mid-6th century and rebuilt in the 1600s, its crenelated walls and many towers stride to the skyline over rolling tree-covered hills. It looks as if it was built yesterday.

That is because parts of it were only ‘restored’ a decade ago. When looking at the wall, amazing though it is, I find it hard not to recall the axe that has been in the family for three generations: my grandfather replaced the shaft and my father replaced the head. Who knows what is authentic any more?

At Mutianyu, I take a cable car to the top of the wall and enjoy an exciting, if incongruous, toboggan slide back down on a steel track. Shopkeepers offer me every imaginable souvenir, from wall hangings and T-shirts to talking pandas and Red Guard alarm clocks. Chinese “warriors” provide photo ops and the main street of the village throbs with a constant stream of tourist coaches. Dotted with recycling bins and solar panels, I am in the midst of modern China, conscious of its role as a showpiece for socialist progress, but thriving on raw capitalism.

Nearby Yingbeigou shows how Mutianyu would be without the prosperity the wall brings. I wander through a village that is picturesque in its poverty, where coal cooking fires smoulder and garbage gathers by the roadside. Famous for chestnuts, the trees were planted and the village founded when workers came here six centuries ago during the Ming Dynasty to build these defensive walls for Beijing, only 45 miles (70 km) away. Now it is a quiet backwater, popular with foreigners who are buying up the old houses, where the young people have left to find work and excitement elsewhere, leaving the older generation to tend its fields and many orchards.

Unesco put the Great Wall on the World Heritage list in 1987, which has spurred an effort to look after what remains. Local people have long stripped its bricks and stones for houses and farm buildings, while roads have been driven through sections more than 2,000 years old with no thought of preservation.

Mining, both legal and illegal, has caused the collapse of great swathes, including nearly 700 metres of the Ming wall near Beijing in October 2011. It is estimated that two-thirds of it may have gone already. “There never actually was such a thing as the ‘Great Wall’ in the sense of one continuous fortification,” says Lin Xuĕ. There are a series of walls and trenches, built many centuries apart, as well as natural barriers such as hills and rivers, that cover China’s northern borders and the official length has recently been measured at 8,851.8 km. In American terms, that is the distance from Boston to San Francisco – and back again.

The first mud-brick Han Dynasty walls were built from around 200 BCE to 200 AD. The Ming Dynasty walls that we see in most photographs of the Great Wall date mainly to the 16th century and measure a total of 6,260 km. The Badaling section sits on massive stone blocks, some weighing up to a ton but even these fortifications ultimately proved ineffective against nomadic warriors who could simply ride around them. In 1644, the Manchu army did just that, capturing Beijing and establishing the Ch’ing dynasty which lasted until 1912.

“The Great Wall was a great deal of effort that ultimately failed in its purpose,” says Lin. “The Ming wall was a sign of weakness, not strength, built using slave labour by a dynasty that collapsed because of its own internal failings. It was a massive waste of resources and both the quarrying and the tree cutting needed to open up clear lines of fire for defenders and grow crops to feed its garrison caused China’s first environmental disaster.”

The Wall is so long that it is hard to imagine a beginning. In the west, Jiayuguan marks one end, standing on the natural defensive barrier of a steep-gorged river and guarding entry to the Hexi Corridor.

Nicknamed the ‘throat of China’, this 1,000 km-long stretch of arid land with the pitiless Gobi Desert to the north, hemmed in by the snow-capped mountains to the south, forced travellers onto a route through its few oases – easy to control and guard. This is one of the contradictions of the Great Wall. While we tend to think of it as a barrier against invasion, thereby protecting China from foreign influence, this part of it at least was designed to protect trade on the Silk Road and hence open the country up.

Jiayuguan (meaning Excellent Valley Pass) has a fierce reputation among Chinese people. It was once the place from which those who had offended the emperor would be sent into exile: the end of the world. Given how much effort went into the Great Wall to defend China from the ‘barbarians’, one can imagine it must have been a terrifying prospect to be sent out among them, even leaving aside the inhospitable landscape of desert and peaks. Now it is an interesting modern city whose desert setting and surprising nightlife oddly remind me of a mini-Vegas, apart from the winter snow dusting the ground. The people are much friendlier than around Beijing, too, perhaps because they are less used to foreigners.

The impressive Jiayuguan Fort has been heavily restored, some of it in concrete that has caused the mud bricks to fail under the weight. Unthinking reconstruction such as this may be as great a danger to the wall as neglect. On the other hand the “First Beacon Tower of the Great Wall”, the much-photographed start of the wall itself, has crumbled to a dull-looking pile of mud bricks. The spectacular gorge it stands beside is well worth the visit, though, but the bitter January winds soon force me back inside out of the cold.

The wind has attacked this western part of the Great Wall with a vengeance. Built from rammed earth bound with a now-lost recipe of straw, tamarisk, egg yolk and rice paste, it is disintegrating under the slow assault of the elements. Flash floods and sandstorms have also helped smooth the edges between wall and the sandy ground it grew out of, while overgrazing and unsuitable land use helps the crushing advance of the Gobi. Nature is a more patient besieger than any foreign army.

This is one of the most ancient parts of the wall, as much as 2,000 years old and showing every sign of its age. Standing on any part that remains, I risk it crumbling beneath my weight, destroying what I have come to see. With more wall than most of us could explore in a lifetime, any such loss might appear relatively unimportant. However, the Chinese name of “Long Wall” reminds us that its real significance is its length, and losing any of it makes it no longer “Great”.

Out here, on the desert edge, my thoughts are free to roam and the winds conjure up the spirits of the countless labourers who died building it, the soldiers whose lives were passed in patrolling it and the attackers who studied it as a life-and-death obstacle. All gone, with the wall their only memorial. Now it too crumbles to dust, recalling the poem by Shelley about the traveller who comes upon a fallen, once-mighty statue in the desert with the poignant inscription: “My name is Ozymandias, king of kings: Look on my works, ye Mighty, and despair!”

The wall, designed to keep out foreigners, failed to do so and in many ways its scale is more of a tribute to the invaders that its builders. After all, as the Berlin Wall proved centuries later, every wall has two sides. In reality, the wall is both larger and smaller than in our minds. The shapeless sections still standing in Gansu and Inner Mongolia look like giant sandcastles built by children, leaving it to the imagination to conjure up former glories. However, seeing it stretch endlessly elsewhere over hills to the horizon makes it seem, like Europe’s cathedrals or New York’s skyline, greater than its mere man-made detail.

Once, it merely represented oppression by the emperors who forced their people to build it, with perhaps one million workers dying in the process, a powerful message for Communism to seize on to. In the 1960s, Mao Zedong’s Red Guards destroyed sections of the wall they termed a relic of feudalism. Businesswoman Wu Ying (55) says: “I always think the Great Wall is haunted because so many people died building it.”

It was only in the 1980s that the government began promoting it as a symbol of Chinese identity when Deng Xiaoping, Mao’s successor, declared: “Love China, Restore the Great Wall.” As tensions rose between the various ethnic groups that make up modern China, it was spun as a joint effort by all of them. “If we built such a wonder together, then we must be one people,” is the message. It has become a symbol of unity.

“Growing up in China and educated by the standard textbooks, the Great Wall, along with the Dragon, Panda and the colour Red, are almost irreplaceable symbols of China,” says Lin Xuĕ, now in her mid-30s, “not only under the Communist regime and current government, but China in a historical, traditional, and cultural sense. This is the education I had, and I believe this same deeply rooted mindset applies not only to elder generations who had a stricter education than me, but also today’s generations who have much more access to the outside world.”

Chinese poet Lu Xun foresaw how this new interpretation would in a sense herd the Chinese people within it. He wrote in 1935: “I have always felt hemmed in on all sides by the Great Wall; that wall of ancient bricks which is constantly being reinforced. The old and the new conspire to confine us all. When will we stop adding new bricks to the Wall? The Great Wall of China: a wonder and a curse.”